1. Field of the Invention
The invention relates to repairing wooden pallets and, more particularly, to a method and apparatus for repairing such pallets in a particularly efficient manner.
2. Reference to Related Patents
Reference is hereby made to application Ser. No. 09/080,790, filed concurrently by Timothy R. Beane, entitled Machine for Removing Stringers from Pallets (hereinafter "the Stringer Removal Patent"); U.S. Pat. No. 5,943,766, application Ser. No. 09/080,830, filed concurrently by Timothy R. Beane, entitled Machine for Inserting Stringers into Pallets (hereinafter "the Stringer Insertion Patent"); and application Ser. No. 09/080,673, filed concurrently by Timothy R. Beane, entitled Machine for Removing Deckboards from Pallets (hereinafter "the Deckboard Removal Patent"), the disclosures of which are incorporated herein by reference.
3. Description of the Prior Art
Load-bearing pallets fabricated of wooden components frequently are used to transport and store various articles, machines, or materials. Such pallets generally are of two types: the stringer type and the block type. Stringer-type pallets include three spaced, parallel support members to which upper and lower deckboards are nailed. Block-type pallets employ a number of relatively small, spaced blocks to which upper and lower deckboards are nailed. The spaces between the stringers or the blocks are adapted to receive the tines of conventional forklift trucks.
In the course of being moved from place to place, the pallets frequently become damaged. If a damaged pallet is not repaired, it must be discarded because of its inability to safely and securely support and transport articles or materials. Because a new pallet is expensive, it is desirable to repair damaged pallets rather than to buy new ones, if possible.
End users of the pallets usually have no capability to repair pallets. As a consequence, pallet repair facilities have been established. Pallet repair facilities collect pallets from end users (or pay independent contractors to collect the pallets), repair the pallets, and sell the pallets to new users. In certain circumstances, the pallets will be owned by a company that leases the pallets to its users. In such cases, pallet repair facilities will repair the leased pallets for an agreed-upon fee.
Due to the large number of pallets that must be repaired, it is important that high quality pallet repairs be done quickly and inexpensively. Unfortunately, pallet repairs usually are done by hand. That is, damaged pallets must be partially or totally disassembled with crowbars or similar manual tools and reassembled with new components. Although machines are available that totally dismantle pallets, such machines usually cannot be used to remove and replace selected components of a pallet. See, for example, U.S. Pat. Nos. 4,241,459; 4,320,570; 4,750,255; 4,945,626; 5,105,526; 5,211,094; 5,205,197; 5,243,751; 5,307,554; 5,323,525; 5,414,924; and 5,600,882 for teachings of representative pallet dismantling machines.
During the course of processing, the pallets must be lifted and inverted by hand. When deckboards must be separated in order to remove and replace defective stringers or blocks, the separation is accomplished by hand tools. The extensive manual labor required to repair pallets is a limiting factor in the speed (and, hence, the cost) with which a pallet can be repaired.
Because pallet repair involves a great deal of manual labor, there is a risk of injury to workers. The pallets are heavy, about 70 or 80 pounds, and thus only physically strong workers are suitable for pallet repair work. The extreme physical requirements for pallet repair work limit the labor pool of suitable workers. Even when suitable workers are available, the demands of the job result in a high worker turnover rate.
Another problem with pallet repair is that all pallets are processed along a single repair line. If a pallet needs a number of components to be replaced, a relatively long time will be needed to repair the pallet. In such cases, several workers may have to work on a single pallet at the same time. On the other hand, if a pallet need only a few number of components to be replaced, a relatively short time will be needed to repair the pallet. By mixing badly damaged pallets with less damaged pallets, the overall time required to process all pallets is increased.
Desirably, a method and apparatus would be available that would enable pallet repairs to be accomplished with a minimum of manual labor and with an increase in processing speed. Such method and apparatus hopefully would minimize the risk of injury to workers while greatly reducing the physical demands that are imposed on the workers.